For a thermocouple,the temperature of inversion is that temperature at which the thermo $e.m.f.$ is:

$A$ coil takes $15\,min$ to boil a certain amount of water,and another coil takes $20\,min$ for the same process. What is the time taken to boil the same amount of water when both coils are connected in series?

The temperature of the cold junction and the neutral temperature of a thermocouple are $15\,^{\circ}C$ and $280\,^{\circ}C$ respectively. The temperature of inversion is .............. $^{\circ}C$.

One junction of a certain thermoelectric couple is at a fixed temperature $T_r$ and the other junction is at temperature $T$. The thermo-electromotive force for this is expressed by $E=k(T-T_r)[T_0-\frac{1}{2}(T+T_r)]$. At temperature $T=\frac{1}{2} T_0$, the thermoelectric power is

If for a thermocouple ${T_n}$ is the neutral temperature,${T_c}$ is the temperature of the cold junction,and ${T_i}$ is the temperature of inversion,then:

An electric kettle has two coils. When one coil is switched on,the tea gets heated in $10 \, \text{min}$. When the other coil is switched on,the same amount of tea gets heated in $40 \, \text{min}$. If both coils are connected in parallel,how long will it take to heat the same amount of tea (in $, \text{min}$)?